As discussed on the other mail thread:
https://www.postgresql.org/message-id/696885c3db9be6.68269280.fb0eaf68%40m0.mail.sina.com.cn
I need to do two changes on the patch.
1. Find some way to handle static variables.
2. Do not collect useless pages on the third step.
For the first one because the static variables needed on several place and it seem worst if
deliver by function parameters, so I keep them.
For the second one I have tryied to keep a commited transaction ID list or bitmapset, however
the data structs seem hard to use in src/bin code. So I use min_commited_xid and
max_commited_xid instead to filter the useless pages.
In fact the min_commited_xid and max_commited_xid is the edge transaction commited after
diverge record, so it's enough.
Changed patch attached.
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Best Regards,
Movead Li
